A state/event fault tree(SEFT)is a modeling technique for describing the causal chains of events leading to failure in software-controlled complex systems.Such systems are ubiquitous in all areas of everyday life,and ...A state/event fault tree(SEFT)is a modeling technique for describing the causal chains of events leading to failure in software-controlled complex systems.Such systems are ubiquitous in all areas of everyday life,and safety and reliability analyses are increasingly required for these systems.SEFTs combine elements from the traditional fault tree with elements from state-based techniques.In the context of the real-time safety-critical systems,SEFTs do not describe the time properties and important timedependent system behaviors that can lead to system failures.Further,SEFTs lack the precise semantics required for formally modeling time behaviors.In this paper,we present a qualitative analysis method for SEFTs based on transformation from SEFT to timed automata(TA),and use the model checker UPPAAL to verify system requirements’properties.The combination of SEFT and TA is an important step towards an integrated design and verification process for real-time safety-critical systems.Finally,we present a case study of a powerboat autopilot system to confirm our method is viable and valid after achieving the verification goal step by step.展开更多
The propagation of single-event effects(SEEs)on a Xilinx Zynq-7000 system on chip(SoC)was inves-tigated using heavy-ion microbeam radiation.The irradia-tion results reveal several functional blocks’sensitivity locati...The propagation of single-event effects(SEEs)on a Xilinx Zynq-7000 system on chip(SoC)was inves-tigated using heavy-ion microbeam radiation.The irradia-tion results reveal several functional blocks’sensitivity locations and cross sections,for instance,the arithmetic logic unit,register,D-cache,and peripheral,while irradi-ating the on-chip memory(OCM)region.Moreover,event tree analysis was executed based on the obtained microbeam irradiation results.This study quantitatively assesses the probabilities of SEE propagation from the OCM to other blocks in the SoC.展开更多
Background:Ongoing climate change is anticipated to increase the frequency and intensity of drought events,thereby affecting forest recovery dynamics and elevating tree mortality.The drought of 2018,with its exception...Background:Ongoing climate change is anticipated to increase the frequency and intensity of drought events,thereby affecting forest recovery dynamics and elevating tree mortality.The drought of 2018,with its exceptional intensity and duration,had a significant adverse impact on tree species throughout Central Europe.However,our understanding of the resistance to and recovery of young trees from drought stress remains limited.Here,we examined the recovery patterns of native deciduous tree sapling species following the 2018 drought,and explored the impact of soil depth,understory vegetation,and litter cover on this recovery.Methods:A total of 1,149 saplings of seven deciduous tree species were monitored in the understory of old-growth forests in Northern Bavaria,Central Germany.The vitality of the saplings was recorded from 2018 to 2021 on 170 plots.Results:Fagus sylvatica was the most drought-resistant species,followed by Betula pendula,Acer pseudoplatanus,Quercus spp.,Corylus avellana,Carpinus betulus,and Sorbus aucuparia.Although the drought conditions persisted one year later,all species recovered significantly from the 2018 drought,albeit with a slight decrease in vitality by 2021.In 2018,the drought exhibited a more pronounced adverse effect on saplings in deciduous forests compared to mixed and coniferous forests.Conversely,sapling recovery in coniferous and mixed forests exceeded that observed in deciduous forests in 2019.The pivotal factors influencing sapling resilience to drought were forest types,soil depth,and understory vegetation,whereas litter and forest canopy cover had a negative impact.Conclusion:Long-term responses of tree species to drought can be best discerned through continuous health monitoring.These findings demonstrate the natural regeneration potential of deciduous species in the context of climate change.Selective tree species planting,soil management practices,and promoting understory diversity should be considered when implementing adaptive management strategies to enhance forest resilience to drought events.展开更多
In this paper,the irrational-behavior-proof conditions in a class of stochastic dynamic games over event trees are presented.Four kinds of irrational-behavior-proof conditions are proposed by the imputation distributi...In this paper,the irrational-behavior-proof conditions in a class of stochastic dynamic games over event trees are presented.Four kinds of irrational-behavior-proof conditions are proposed by the imputation distribution procedure,and their relationships are discussed.More specific properties for the general transformation of characteristic functions are developed,based on which,the irrational-behavior-proof conditions are proved to be true in a transformed cooperative game.展开更多
基金supported by the National Natural Science Foundation of China(11832012)
文摘A state/event fault tree(SEFT)is a modeling technique for describing the causal chains of events leading to failure in software-controlled complex systems.Such systems are ubiquitous in all areas of everyday life,and safety and reliability analyses are increasingly required for these systems.SEFTs combine elements from the traditional fault tree with elements from state-based techniques.In the context of the real-time safety-critical systems,SEFTs do not describe the time properties and important timedependent system behaviors that can lead to system failures.Further,SEFTs lack the precise semantics required for formally modeling time behaviors.In this paper,we present a qualitative analysis method for SEFTs based on transformation from SEFT to timed automata(TA),and use the model checker UPPAAL to verify system requirements’properties.The combination of SEFT and TA is an important step towards an integrated design and verification process for real-time safety-critical systems.Finally,we present a case study of a powerboat autopilot system to confirm our method is viable and valid after achieving the verification goal step by step.
基金This work was supported by the National Natural Science Foundation of China(Nos.11575138,11835006,11690040,11690043,and 11705216)the Innovation Center of Radiation Application(No.KFZC2019050321)the China Scholarships Council program(No.201906280343).
文摘The propagation of single-event effects(SEEs)on a Xilinx Zynq-7000 system on chip(SoC)was inves-tigated using heavy-ion microbeam radiation.The irradia-tion results reveal several functional blocks’sensitivity locations and cross sections,for instance,the arithmetic logic unit,register,D-cache,and peripheral,while irradi-ating the on-chip memory(OCM)region.Moreover,event tree analysis was executed based on the obtained microbeam irradiation results.This study quantitatively assesses the probabilities of SEE propagation from the OCM to other blocks in the SoC.
文摘Background:Ongoing climate change is anticipated to increase the frequency and intensity of drought events,thereby affecting forest recovery dynamics and elevating tree mortality.The drought of 2018,with its exceptional intensity and duration,had a significant adverse impact on tree species throughout Central Europe.However,our understanding of the resistance to and recovery of young trees from drought stress remains limited.Here,we examined the recovery patterns of native deciduous tree sapling species following the 2018 drought,and explored the impact of soil depth,understory vegetation,and litter cover on this recovery.Methods:A total of 1,149 saplings of seven deciduous tree species were monitored in the understory of old-growth forests in Northern Bavaria,Central Germany.The vitality of the saplings was recorded from 2018 to 2021 on 170 plots.Results:Fagus sylvatica was the most drought-resistant species,followed by Betula pendula,Acer pseudoplatanus,Quercus spp.,Corylus avellana,Carpinus betulus,and Sorbus aucuparia.Although the drought conditions persisted one year later,all species recovered significantly from the 2018 drought,albeit with a slight decrease in vitality by 2021.In 2018,the drought exhibited a more pronounced adverse effect on saplings in deciduous forests compared to mixed and coniferous forests.Conversely,sapling recovery in coniferous and mixed forests exceeded that observed in deciduous forests in 2019.The pivotal factors influencing sapling resilience to drought were forest types,soil depth,and understory vegetation,whereas litter and forest canopy cover had a negative impact.Conclusion:Long-term responses of tree species to drought can be best discerned through continuous health monitoring.These findings demonstrate the natural regeneration potential of deciduous species in the context of climate change.Selective tree species planting,soil management practices,and promoting understory diversity should be considered when implementing adaptive management strategies to enhance forest resilience to drought events.
基金supported by National Natural Science Foundation of China(No.72171126)China Postdoctoral Science Foundation(No.2016M600525)Qingdao Postdoctoral Application Research Project(No.2016029).
文摘In this paper,the irrational-behavior-proof conditions in a class of stochastic dynamic games over event trees are presented.Four kinds of irrational-behavior-proof conditions are proposed by the imputation distribution procedure,and their relationships are discussed.More specific properties for the general transformation of characteristic functions are developed,based on which,the irrational-behavior-proof conditions are proved to be true in a transformed cooperative game.
